Handler基本概念： Handler主要用于异步消息的处理：当发出一个消息之后，首先进入一个消息队列，发送消息的函数即刻返回，而另外一个部分逐个的在消息队列中将消息取出，然后对消息进行出来，就是发送消息和接收消息不是同步的处理。 这种机制通常用来处理相对耗时比较长的操作。 Handler 常用方法：

post(Runnable)

postAtTime(Runnable,long)

postDelayed(Runnable long)

sendEmptyMessage(int)

sendMessage(Message)

sendMessageAtTime(Message,long)

sendMessageDelayed(Message,long)

以上post类方法允许你排列一个Runnable对象到主线程队列中, sendMessage类方法, 允许你安排一个带数据的Message对象到队列中，等待更新.

Android三种实现定时器的方法

方法一:Handler+Thread

package com.xunfang.handerDemo;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.widget.TextView;

/**

 * handler定时器

 *

 * @author Smalt

 *

 */

public class HanderDemoActivity extends Activity {

	TextView tvShow;

	private int i = 0;

	@Override

	public void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.main);

		tvShow = (TextView) findViewById(R.id.tv_show);

		new Thread(new ThreadShow()).start();

	}

	// handler类接收数据

	Handler handler = new Handler() {

		public void handleMessage(Message msg) {

			if (msg.what == 1) {

				tvShow.setText(Integer.toString(i++));

				System.out.println("receive....");

			}

		};

	};

	// 线程类

	class ThreadShow implements Runnable {

		@Override

		public void run() {

			// TODO Auto-generated method stub

			while (true) {

				try {

					Thread.sleep(1000);

					Message msg = new Message();

					msg.what = 1;

					handler.sendMessage(msg);

					System.out.println("send...");

				} catch (Exception e) {

					// TODO Auto-generated catch block

					e.printStackTrace();

					System.out.println("thread error...");

				}

			}

		}

	}

}

方法二:Handler类自带的postDelyed

package com.xunfang.handerDemo;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.widget.TextView;

/**

 * handler定时器使用postDelyed实现

 *

 * @author Smalt

 *

 */

public class HanderDemoActivity extends Activity {

	TextView tvShow;

	private int i = 0;

	private int TIME = 1000;

	@Override

	public void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.main);

		tvShow = (TextView) findViewById(R.id.tv_show);

		handler.postDelayed(runnable, TIME); //每隔1s执行

	}

	Handler handler = new Handler();

	Runnable runnable = new Runnable() {

		@Override

		public void run() {

			// handler自带方法实现定时器

			try {

				handler.postDelayed(this, TIME);

				tvShow.setText(Integer.toString(i++));

				System.out.println("do...");

			} catch (Exception e) {

				// TODO Auto-generated catch block

				e.printStackTrace();

				System.out.println("exception...");

			}

		}

	};

}

方法三:

Handler+Timer+TimerTask